// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_LOADER_DETACHABLE_RESOURCE_HANDLER_H_
#define CONTENT_BROWSER_LOADER_DETACHABLE_RESOURCE_HANDLER_H_

#include <memory>

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "content/browser/loader/resource_controller.h"
#include "content/browser/loader/resource_handler.h"

namespace net {
class IOBuffer;
class URLRequest;
} // namespace net

namespace content {

// A ResourceHandler which delegates all calls to the next handler, unless
// detached. Once detached, it drives the request to completion itself. This is
// used for requests which outlive the owning renderer, such as <link
// rel=prefetch> and <a ping>. Requests do not start out detached so, e.g.,
// prefetches appear in DevTools and get placed in the renderer's local
// cache. If the request does not complete after a timeout on detach, it is
// cancelled.
//
// Note that, once detached, the request continues without the original next
// handler, so any policy decisions in that handler are skipped.
class DetachableResourceHandler : public ResourceHandler,
                                  public ResourceController {
public:
    DetachableResourceHandler(net::URLRequest* request,
        base::TimeDelta cancel_delay,
        std::unique_ptr<ResourceHandler> next_handler);
    ~DetachableResourceHandler() override;

    bool is_detached() const { return next_handler_ == NULL; }
    void Detach();

    void set_cancel_delay(base::TimeDelta cancel_delay)
    {
        cancel_delay_ = cancel_delay;
    }

    // ResourceHandler implementation:
    void SetController(ResourceController* controller) override;
    bool OnRequestRedirected(const net::RedirectInfo& redirect_info,
        ResourceResponse* response,
        bool* defer) override;
    bool OnResponseStarted(ResourceResponse* response, bool* defer) override;
    bool OnWillStart(const GURL& url, bool* defer) override;
    bool OnWillRead(scoped_refptr<net::IOBuffer>* buf,
        int* buf_size,
        int min_size) override;
    bool OnReadCompleted(int bytes_read, bool* defer) override;
    void OnResponseCompleted(const net::URLRequestStatus& status,
        bool* defer) override;
    void OnDataDownloaded(int bytes_downloaded) override;

    // ResourceController implementation:
    void Resume() override;
    void Cancel() override;
    void CancelAndIgnore() override;
    void CancelWithError(int error_code) override;

private:
    std::unique_ptr<ResourceHandler> next_handler_;
    scoped_refptr<net::IOBuffer> read_buffer_;

    std::unique_ptr<base::OneShotTimer> detached_timer_;
    base::TimeDelta cancel_delay_;

    bool is_deferred_;
    bool is_finished_;

    DISALLOW_COPY_AND_ASSIGN(DetachableResourceHandler);
};

} // namespace content

#endif // CONTENT_BROWSER_LOADER_DETACHABLE_RESOURCE_HANDLER_H_
